The present invention, in some embodiments thereof, relates to an electromagnetic signal-emitting stylus used for interaction with a digitizer system and more particularly, but not exclusively to an active and/or self powered stylus.
Styluses are known in the art for use with digitizer systems such as with digitizer systems that are integrated with a display screen, e.g. a touch screen. Stylus position is sensed by the digitizer system and used to provide input to a computing device associated with the display screen. Position of the stylus is typically correlated with virtual information displayed on the display screen. Inputs originating from the stylus are typically interpreted as user commands or user inputs for commands. Typically, a signal emitted by the stylus is detected by the digitizer system both while a writing tip of the stylus is touching and hovering over a detection surface of the digitizer system.
U.S. Pat. No. 7,292,229 entitled “Transparent Digitiser,” assigned to N-Trig Ltd., the contents of which is incorporated herein by reference, describes passive stylus that is a stylus with no internal power source and no wired connection for interaction with a digitizer sensor. It is described that the stylus is energized by a triggering pulse provided with an excitation coil which surrounds the sensor and thereby energizes the stylus resonance circuit. An advantage of external excitation is that it inherently provides synchronization of the stylus to the digitizer, since both components are aware of the excitation pulse timing. It is stated that in alternative embodiments, the stylus may be internally powered using a battery. The stylus further comprises a touch switch and a right click switch. Each of the touch switches when closed have the effect of altering the resonant frequency so that the digitizer system can recognize touch and right click.
U.S. Pat. No. 8,536,471 entitled “Pressure Sensitive Stylus for a Digitizer,” assigned to N-Trig Ltd., the contents of which is incorporated herein by reference, describes a pressure sensitive stylus with a movable tip that recedes within a housing of the stylus in response to user applied contact pressure and an optical sensor enclosed within the housing for optically sensing the displacement of the tip and for providing output in response to the sensing. There is also described a capacitive based displacement sensor including variable capacitor with one conductive plate in physical communication with stylus tip so that it moves in accordance with the stylus tip movement.
U.S. Pat. No. 8,481,872 entitled “Digitizer, Stylus and Method of Synchronization Therewith,” assigned to N-Trig Ltd., the contents of which is incorporated herein by reference, describes a method for operating a digitizer with an autonomous asynchronous stylus includes sampling outputs from a digitizer, detecting from the outputs at least one pulsed signal transmitted from an autonomous asynchronous stylus at a defined rate, determining a location of the stylus interaction with respect to the digitizer, and tracking stylus interaction with the digitizer over subsequent pulsed signals transmitted from the stylus.